Mapping Mountains – Significant Name Changes – The Welsh P15s

Cae Plu (SN 562 035) 

There has been a Significant Name Change to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cae Plu (SN 562 035)

The criteria for the list that this name change applies to are:

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The hill is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with a minor road to its north, the A4138 road to its south and the M4 motorway to its east, and has the town of Llanelli towards the south-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the accompanying sub list under the point (Pt. 106m) notation with an estimated c 14m of drop, based on the 106m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, and an estimated c 92m bwlch height based on interpolation of 5m contouring between 90m – 95m. 

Extract from the Ordnance Survey 1:25,000 Explorer map

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales. 

Extract from the Tithe map

The enclosed land where the summit of this hill is situated is given the number 140 on the Tithe map, this can be cross referenced against the apportionments; it is these apportionments that give the name of the owner or occupier of the land as well as the name of the land.  The land where the summit of this hill is situated is named as Cae Plu in the apportionments, with the details on the Tithe map appearing in the parish named as Llangennech and in the county named as Carmarthen. 

Extract from the apportionments

Therefore, the name this hill is now listed by in The Welsh P15s is Cae Plu and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Cae Plu

Previously Listed Name:  Pt. 106m 

OS 1:50,000 map:  159

Summit Height:  106.65m (LIDAR)                                                           

Summit Grid Reference:  SN 56249 03517 (LIDAR)                                                  

Bwlch Height:  91.5m (LIDAR) 

Bwlch Grid Reference:  SN 56274 03613 (LIDAR) 

Drop:  15.15m (LIDAR) 

 

Myrddyn Phillips (February 2025)

 

 

  

Mapping Mountains – Summit Relocations – The Welsh P15s

 

Cae Plu (SN 562 035) 

There has been a Summit Relocation to a hill that is listed in the The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cae Plu (SN 562 035)

The criteria for the list that this summit relocation applies to are:

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is now listed by is Cae Plu, and this was derived from the Tithe map, and it is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with a minor road to its north, the A4138 road to its south and the M4 motorway to its east, and has the town of Llanelli towards the south-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the accompanying sub list with an estimated c 14m of drop, based on the 106m summit spot height that was positioned at SN 56242 03523 and which appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, and an estimated c 92m bwlch height based on interpolation of 5m contouring between 90m – 95m. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis gives the highest ground on this hill as 107.6m positioned at SN 56243 03507.  However, this is to the top of a raised field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Cae Plu (SN 562 035)

The height produced by LIDAR analysis to the natural summit of this hill is 106.65m and is positioned at SN 56249 03517, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 106.65m and is positioned at SN 56249 03517, this position is relatively close to where the 106m spot height appeared, and is approximately 10 metres north-eastward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Cae Plu 

OS 1:50,000 map:  159

Summit Height:  106.65m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 56249 03517 (LIDAR)                                                  

Bwlch Height:  91.5m (LIDAR) 

Bwlch Grid Reference:  SN 56274 03613 (LIDAR) 

Drop:  15.15m (LIDAR) 

 

Myrddyn Phillips (February 2025)

 

 

 

Mapping Mountains – Hill Reclassifications – The Welsh P15s

 

Cae Plu (SN 562 035) – Welsh Sub-P15 reclassified to Welsh P15

There has been a reclassification to the list of The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cae Plu (SN 562 035)

The criteria for the list that this reclassification applies to are:

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is now listed by is Cae Plu, and this was derived from the Tithe map, and it is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with a minor road to its north, the A4138 road to its south and the M4 motorway to its east, and has the town of Llanelli towards the south-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the accompanying sub list with an estimated c 14m of drop, based on the 106m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, and an estimated c 92m bwlch height based on interpolation of 5m contouring between 90m – 95m. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the reclassification of this hill from Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 106.65m summit height and a 91.5m bwlch height, with these values giving this hill 15.15m 0f drop, which is sufficient for it to be classified as a Welsh P15. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Cae Plu 

OS 1:50,000 map:  159

Summit Height:  106.65m (LIDAR)                                                           

Summit Grid Reference:  SN 56249 03517 (LIDAR)                                                  

Bwlch Height:  91.5m (LIDAR) 

Bwlch Grid Reference:  SN 56274 03613 (LIDAR) 

Drop:  15.15m (LIDAR) 

 

Myrddyn Phillips (January 2025)